Made this on Sunday and it is pretty good! I tripled the recipe and zested the peel rather than sliced it because I wanted fine-cut marmalade. The grenadine gave it a great pinky orange colour and I got just over 7 cups of marmalade.

Edit: Since I have made this several times, I think that I should change my review to 5 stars. I just love it. Thanks! ***My Mom sent us a box of grapefruit for our anniversary. After a while, I started looking for something to do with them! Since my dh loves grenadine, thought I would try this. It turned out lovely. This was my first time making marmalade. I later used some of the marmalade to make Orange Marmalade Cookies which turned out very well. Thank you very much for a lovely recipe.